190 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



9. A. trinodis Arnott (1861). — Linear, gibbous in the middle and at the broad ends. 

 L. 0,015 to 0,02; B. 0,005 mm. Upper V. with narrow axial area dilated in the middle to an 

 almost orbicular, small central area. Strife about 30 in 0,oi mm. parallel. Lower V. without 

 distinct axial area and with small central area. Stria; about 30 in 0,oi mm. parallel. — Achnan- 

 thidium trinode Pritch. Inf. p. 872 PI. VllI f. 9. Nav. trinodis Grdn. Verb. 1860 p. 551 PL IV 

 f. 8. Bhoiconeis irin. Grun. Verb. 1863 p. 147. Achn. trin. V. H. Syn. PL XXVII f. 50 to 52. 



Fresh water: England, Tyrol (Grun.). 



10. A. (lelicatula Kutz. (1844). — Elliptic-lanceolate, frequently with subrostrate ends. 

 L. 0,01 to 0,02; B. 0,005 to 0,011 mm. Upper V. with narrow, linear axial area. Striae 14 to 15 

 in 0,01 mm. almost parallel. Lower V. with indistinct axial area and very small, orbicular central 

 area. Striis 17 to 19 in 0,oi mm. the median shorter. — Achnanthidium delicatulum KtJTZ. Bac. 

 p. 75 PL III f. 21. Achnanthes delic. Grun. A. D. p. 22, 1880. V. H. Syn. p. 130 PL XXVII f. 3, 4. 



Brackish water: Greenland! Arctic America! North Sea! English Channel! Balearic Islands! 

 San Francisco! 



11. A. Haiickiiina Grun. (1880). — Elliptical to elliptic-lanceolate. L. 0,012 to 0,03i; 

 B. 0,006 to 0,008 mm. Upper V. with linear, narrow axial area. Striae 10 to 12 in 0,oi mm., 

 parallel, lower V. without axial area and with small central area. Striae 10 to 13 in 0,oi mm. 

 radiate. — A. D. p. 21. Achn. HaucUi Grun. V. H. Syn. PL XXVII f. 14, 15. 



Hot springs and brackish water: Triest (Grun.), Canada! New Zealand! Tasmania! Cape Horn! 



12. A. afHnis Grun. (1880). — Linear-lanceolate, obtuse. L. 0,oi5 to 0,023; B. 0,oo3 to 

 0,0035 mm. Upper V. with narrow, linear axial area. Striae parallel 27 to 30 in 0, 01 mm. Lower 

 V. with narrow axial area. Central area a transverse fascia, reaching to the margin. Striae about 

 30 in 0,01 mm. radiate throughout. — A. D. p. 20. V. H. Syn. p. 130 PL XXVII f. 39, 40. 



Fresh water: Belgium (V. H.), Tasmania! North America, White Mountains! 

 Var. jamalinensis Grun. (1880). — L. 0,037; B. 0,005 mm. Striae of the lower V. 16 inO,oi 

 mm. — A. hungarica var.? jamal. Grun. A. D. p. 20. 

 Marine (?): Sea of Kara (Grun.). 



13. A. exigua Grun. (1880). — Broadly elliptic-lanceolate, with rostrate, obtuse ends. 

 L. 0,013 to 0,017; B. 0,005 to 0,006 mm. Upper V. with narrow, linear axial area. Striae about 

 22 in 0,01 mm. parallel. Lower V. with very narrow axial area. Central area a transverse 

 fascia, reaching to the margin. Striae about 25 in 0,o 1 mm. slightly radiate throughout. — Stauro- 

 neis exilis KtJTZ. Bac. p. 105 PL XXX f. 21. Schum. Preuss. I). II Nachtr. PL II f. 59. Ach. 

 exigua Grun. A. D. p. 21. V. H. Syn. PL XXVII f. 29, 30. 



Fresh water, hot springs: Sweden (Hernosand, interglacial deposit)! Germany (Berlin)! 

 Brazil! Ecuador! Surinam! Java! New Zealand! Hawaii! 



14. A. hungarica Grun. (1863). — Narrow elliptical or linear-lanceolate with subcuneate 

 ends. L. 0,02 to 0,03; B. 0,oo6 to 0,oo7 mm. Upper V. with narrow axial area, in the middle 

 dilated to a narrow, short, transverse central area. Striae about 21 in 0,oi mm., parallel. Lower 

 V. with narrow axial area. Central area a broad fascia. Striae about 21 in 0,oi mm., slightly 

 radiate. — Achnanthidium hungaricum Grun. Verb. 1863 p. 146 PL IV f. 8. Achnanthes hung. 

 A. D. p. 20. V. H. Syn. p. 130 PL XXVII f. 1, 2. Achnanthidinm neglectum Schum. Preuss. 

 D. II Nachtr. p. 54 PL I f. 17? 



Fresh water: Sweden (Grun.), Belgium (V. H.), Hungary (Grun.), Illinois! Brazil! Ecuador! 

 Australian Alps (Rieva Lagoon)! 



To this group may belong Achnanthes Gregoryana Grbv. (M. J. VII p. 84 PL VI f. 13, 14) 

 if this form, of which the zonal view is figured, be really an Achnanthes, but it appears more 

 probable that it may represent an arcuate Gyrosigma perhaps G. arcticum. 



